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Abstract:

An improved reclining lounge chair is described, which comprises a
footrest that is pivotally connected to a center seat member by a
footrest attachment axle, and in which the footrest position is
controlled by a footrest lift mechanism. While the lounge chair is its
non-reclined upright position the footrest is oriented approximately
vertical. In this approximately vertical orientation the footrest doesn't
extend significantly forward of the center seat member, thus allowing an
occupant easy access to the chair from the front. In its fully reclined
position the footrest rotates into an approximately horizontal
orientation, providing a comfortable reclined position.

Claims:

1. A reclining lounge chair, comprising:a center seat member;a backrest,
the backrest being operatively connected to the center seat member;a
footrest, the footrest being pivotally connected to the center seat
member by a footrest attachment axle;wherein the center seat member, the
backrest, and the footrest form a seat assembly, which is pivotally
connected to a base frame by a seat attachment axle at the center seat
member, andwherein the seat assembly may rotate about the seat attachment
axle between an upright position and a fully reclined position without
changing the relative alignment of backrest and center seat section;a
footrest lift mechanism, the front end of the footrest lift mechanism
being pivotally connected to the footrest by a front footrest lift axle,
and the rear end of the footrest lift mechanism being pivotally connected
to the base frame by a rear footrest lift axle;wherein the rear footrest
lift axle is located below the seat attachment axle, andwherein the
footrest lift mechanism causes the footrest to rotate about the footrest
attachment axle by more than 60.degree. but less than 125.degree. when
the seat assembly is rotated from the upright position to the fully
reclined position.

2. The reclining chair as in claim 1, wherein the footrest rotates by more
than 80.degree. about the footrest attachment axle when the seat assembly
is rotated from the upright position to the fully reclined position.

3. The reclining chair as in claim 1, wherein the footrest rotates by less
than 100.degree. about the footrest attachment axle when the seat
assembly is rotated from the upright position to the fully reclined
position.

4. The reclining chair as in claim 1, wherein the rear footrest lift axle
is located forward of the seat attachment axle.

5. The reclining chair as in claim 1, wherein the rear footrest lift axle
is located below the seat attachment axle.

6. The reclining chair as in claim 1, wherein during regular use the
backrest is at a predetermined, fixed angle relative to the center seat
member, and wherein the backrest can be folded onto the center seat
member to assume a storage position.

7. The reclining chair as in claim 1, wherein the rear footrest lift axle
is located above the seat attachment axle.

8. The reclining chair as in claim 1, wherein the front footrest lift axle
is forward of the footrest attachment axle while the chair is in its
upright position.

9. The reclining chair as in claim 1, wherein the front footrest lift axle
is rearward of the footrest attachment axle while the chair is in its
fully reclined position.

10. The reclining chair as in claim 1, wherein the distance between the
seat attachment axle and the rear footrest lift axle is less than 15% of
the height of the seat attachment axle from the floor.

11. The reclining chair as in claim 1, wherein the distance between the
footrest attachment axle and the front footrest lift axle is less than
15% of the height of the seat attachment axle from the floor.

12. The reclining chair as in claim 1, wherein the front footrest lift
axle is at a height between the footrest attachment axle and the floor.

13. The reclining chair as in claim 1, whereinthe base frame comprises two
base frame members, one of which is located left of the seat assembly and
one of which is located right of the seat assembly, and whereinthe
footrest lift mechanism comprises two footrest lift bars, which are
located inside of and adjacent to each of the two base frame members.

14. The reclining chair as in claim 1, further comprising a latch
mechanism, which latches the chair in one of two or more predetermined
reclining positions.

15. The reclining chair as in claim 14, wherein the latch mechanism is
located between two parts of the chair that rotate relative to each other
while reclining.

16. The reclining chair as in claim 14, wherein the latch mechanism is
located on the inside of the base frame around the rear footrest lift
axle.

17. The reclining chair as in claim 14, wherein the latch mechanism
comprisesa latch disk with alternating radially aligned protrusions and
recesses that is attached torsionally rigid to the base frame, anda
sliding element which rotates about the disk's center axis,wherein the
sliding element comprises at least one protrusion, which is pushed into
the latch disk by a latch spring.

18. The reclining chair as in claim 17, comprising two or more identical
protrusions and recesses.

19. The reclining chair as in claim 17, comprising two or more protrusions
and recesses which are different in at least one of size, width, and
slope angle.

Description:

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001]This is a continuation of international patent application
PCT/EP2007/006864, filed Aug. 2, 2007, which designated the United
States, and which claimed priority to German patent application No. 10
2006 039 278.7, filed Aug. 22, 2006. These applications are hereby
incorporated by reference.

TECHNICAL FIELD

[0002]The present invention generally relates to a reclining lounge chair,
and more particularly, to a reclining lounge chair comprising a footrest
lift mechanism.

BACKGROUND OF THE INVENTION

[0003]Lounge chairs, which can be adjusted between an upright position and
a reclined position, are well known. A category-defining reclining lounge
chair is described in FR 635,465 A. This known chair comprises a
footrest, which is connected to a seat by a horizontal pivot axis. An
adjusting lever mechanism is provided, which is pivotally supported by a
horizontal support axle relative to the frame. The opposite end of the
adjusting lever mechanism is pivotally supported by the footrest through
a horizontal support axle.

[0004]A reclining lounge chair comprising a seat, a backrest, and a
footrest, is described in EP 0,358,666 B1, invented by the same inventor
hereof. The backrest is pivotally joined to the seat by a horizontal
axle, and the seat is pivotally joined to the footrest by a horizontal
axle, respectively. Thereby, the seating and lounge chair can be folded,
such that the footrest, the seat, and the backrest are located
essentially parallel to each other.

[0005]The reclining lounge chair of EP 0,358,666 can be adjusted into a
semi-reclined lounge position, in which the backrest points upward and
rearward, extending from the rear end of the seat. The footrest points
downward and forward from the front end of the seat towards the floor.
From this position the lounge chair can be adjusted into a fully reclined
sleeping position, in which footrest, seat, and backrest are essentially
located in a continuous horizontal plane. This style of reclining lounge
chairs has been well accepted in the market.

[0006]In variation therefrom other reclining lounge chairs exist.
Reclining lounge chairs are known, which comprise an integral couch frame
comprising a center seat section, a backrest section, and footrest
section. In such chairs the backrest section is positioned at a fixed
predetermined small angle relative to the center seat section, and the
center seat section is positioned at a fixed predetermined small angle
relative to the footrest section. The integral couch frame can pivot
about a single horizontal axis relative to a base frame. Such lounge
chairs, known as "health loungers", can often be found in baths,
sanatoriums, etc. An occupant can adjust such lounge chairs by shifting
his or her weight. The lounge chair can typically be adjusted between an
upright position, in which the front end of the integral couch frame
touches the floor, and a fully reclined position, in which the footrest
is aligned approximately horizontal.

[0007]An advantage of these "health loungers" is their simple design,
since the entire couch frame is connected with the base frame by a single
horizontal axle, around which the chair can pivot. No further hinges
between backrest and seat or between seat and footrest are provided.
Disadvantageous, however, is that getting in and out of such couches is
cumbersome, especially for elderly persons. In order to sit down an
occupant may enter from the front, but that requires walking backward
with legs spread far apart to clear the footrest. Alternatively an
occupant can attempt to enter or exit the couch from the side, but that
is difficult due to armrests blocking access to the couch from the side.

[0008]Based on the previously described "health lounger" it is an object
of the current invention to provide an improved reclining lounge chair,
that can be adjusted between at least an upright position and a reclined
position, and that has ergonomic advantages over known health loungers.

SUMMARY OF THE INVENTION

[0009]In one aspect of the invention, a reclining lounge chair is
provided, which comprises a footrest that is pivotally connected to a
center seat member by a footrest attachment axle. A footrest lift
mechanism is operatively connected to the footrest. The footrest lift
mechanism causes the footrest to rotate about the footrest attachment
axle as the lounge chair is reclined. While the lounge chair is in its
non-reclined, upright position, the footrest is oriented approximately
vertical. In this approximately vertical orientation the footrest doesn't
extend significantly forward of the center seat member, thus allowing an
occupant easy access to the chair from the front. The center seat member
may be at a height from the floor that is typical for chairs, which
allows an occupant to easily get in and out of the lounge chair while in
the upright position. This ergonomic design is a significant improvement
over the previously described health lounges, which have fixed footrests
that extend forward of the center seat member at all times.

[0010]The reclining lounge chair may comprise a seat and backrest
subassembly, which is pivotally connected to a base frame by a seat
attachment axle. Also operatively connected to the base frame is the rear
end of the footrest lift mechanism. The front end of the footrest lift
mechanism is operatively connected to the footrest. An occupant may
adjust the lounge chair from the upright position into a reclined
position, simply by shifting his or her weight. This causes the seat and
backrest subassembly to rotate about the seat attachment axle. Rotation
of the seat and backrest subassembly causes the footrest lift mechanism
to simultaneously rotate the footrest about the footrest attachment axle
relative to the center seat member. When the lounge chair reaches its
fully reclined position the footrest may have rotated from its original
approximately vertical orientation into an approximately horizontal
orientation, thus providing a comfortable sleeping position.

[0011]To exit, the lounge chair may be adjusted back into the upright
position. During the adjustment the footrest lift mechanism causes the
footrest to rotate from its approximately horizontal orientation back
into its approximately vertical orientation, pointing downward from the
footrest attachment axle towards the floor. The vertical orientation of
the footrest while the chair is in its upright position allows an
occupant to easily exit, as the footrest does not obstruct the exit path.

[0012]Generally, recliners are known, which through a weight shift or by
adjusting the backrest, allow a footrest to rotate into an elevated
position. Such recliners, however, comprise comparatively complex
adjustment mechanisms, often including scissor style rods. In contrast,
the disclosed design is relatively simple, and requires only a single
footrest lift mechanism. Due to its simple design the described lounge
chair may be used outdoors, for examples in backyards or baths, or
commercially, e.g. in hospitals, indoor public swimming pools, etc.

[0013]In another aspect of the invention, the footrest lift mechanism may
comprise two footrest lift bars, one on each side of the lounge chair.
Each footrest lift bar may be pivotally connected at its front end to the
footrest by a front footrest lift axle, and at its rear end to the base
frame by a rear footrest lift axle. The footrest lift bars may be aligned
almost congruent with the center seat member. To achieve this, the rear
footrest lift axle may be located close to the seat attachment axle,
preferably below and/or in front of the seat attachment axle. Similarly,
the front footrest lift axle may be located close to the footrest
attachment axle, and preferably in front of the footrest attachment axle.
The footrest may comprise an embedded extension shape to provide
sufficient attachment space for both the footrest lift axle and the
footrest attachment axle.

[0014]In a further aspect of the invention, the front footrest lift axle
and the rear footrest lift axle may be located such, that a line drawn
from the front to the rear footrest lift axle intersects a line drawn
from the footrest attachment axle to the seat attachment axle.

[0015]In yet another aspect of the invention a latch mechanism may be
provided to prevent the reclining chair from changing its position too
easily, especially to prevent movement of the chair caused by unintended
weight shifts of larger occupants. The latch mechanism may lock the chair
in one or more predetermined reclining positions.

[0016]The latch mechanism may comprise a sliding arm, which rotate
relative to a latch disk, as the chair is reclined. The sliding arm may
be spring-loaded, compressing a latch spring upon axial movement away
from the latch disk. The sliding arm may comprise one or more
protrusions, that engage one or more radially extending recesses in the
latch disk as the chair reaches predetermined reclining positions. Vice
versa, the sliding arm may comprise recesses that engage protrusions on
the latch disk.

[0017]While the chair is in its upright position one or more protrusions
at the sliding arm resiliently engage one or more recesses at the latch
disk. When the chair is reclined the sliding arm rotates about an axle
extending through the center of the latch disk. This forces the one or
more protrusions of the sliding arm to leave the corresponding recesses
at the latch disk. The sliding arm is pushed axially along its pivot axis
in the center of the latch disk away from the latch disk, thereby
compressing the latch spring. Upon reaching a second predetermined
reclining position the protrusions at the sliding arm resiliently
reengage a second set of recesses in the latch disk, causing the chair to
assume a stable, predetermined reclining position. An adjustment force
larger than the latch force is required to change the chair's position
after it has reached one of its predetermined positions.

[0018]The latch disk may comprise a plurality of recesses to define a
plurality of predetermined stable reclining positions. Similarly, the
sliding arm may comprise a plurality of protrusions to define a plurality
of predetermined stable reclining positions. Protrusions and recesses may
be substituted for each other, i.e. the recesses may be located at the
sliding arm and protrusions may be located at the latch disk.

[0019]The sliding arm and the latch disk of the latch mechanism may
comprise a number of identical protrusions and/or recesses to cause the
same latch force in each position. They may also comprise differently
shaped protrusions and/or recesses to cause different latch forces for
different reclining positions. Using different latch forces for different
reclining positions can be used to compensate an undesirable effect:
Without a latch mechanism the force required to adjust the chair out of
its fully reclined position would be higher than the force required to
adjust the chair out of an intermediate reclining position. Similarly,
the force required to adjust the chair out of its upright position may be
higher than the force required to adjust the chair out of an intermediate
position. In an intermediate position the chair may be exactly balanced
between rotating forward and backward, thus requiring almost no
adjustment force. The required adjustment force is ultimately a function
of where the occupant's center of gravity is located relative to the seat
attachment axle. To require similar or equal adjustment forces in all
three positions, the recesses of the latch disk associated with the
upright position may have a shallow front exit, causing a relatively low
latch force to exit the upright position. In the intermediate position
the recesses may have a steeper angle to increase the latch force that
must be overcome to adjust the chair out of the intermediate position.

[0020]The following detailed description of the invention is merely
exemplary in nature and is not intended to limit the invention or the
application and uses of the invention. Furthermore, there is no intention
to be bound by any theory presented in the preceding background of the
invention or the following detailed description of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021]The invention is further explained with reference to the following
drawings.

[0022]FIG. 1a illustrates a known "health lounger" in an upright position.

[0023]FIG. 1b illustrates the "health lounger" of FIG. 1a in a reclined
position.

[0024]FIG. 2 is a side view of an exemplary reclining lounge chair in the
upright position.

[0025]FIG. 3 is a side view of the reclining lounge chair as in FIG. 2,
shown in a fully reclined position.

[0026]FIG. 4 is a side view of the reclining lounge chair as in FIGS. 2
and 3, shown in a folded state.

[0027]FIG. 5 is a schematic view of the reclining lounge chair as in FIG.
2.

[0028]FIG. 6 is a schematic view of the reclining lounge chair as in FIG.
3.

[0029]FIG. 7 is a schematic view overlaying the schematic views of FIG. 5,
FIG. 6, and a third intermediate reclining position.

[0030]FIGS. 8a and 8b are a side view and a top view of an exemplary latch
mechanism showing the mechanism engaged in a first engaged state.

[0031]FIGS. 9a and 9b are showing the latch mechanism of FIGS. 8a and 8b
in an intermediate position between a first and a second engaged state.

[0032]FIGS. 10a and 10b are showing the latch mechanism of FIGS. 8a and 8b
after reaching a second engaged state.

[0033]FIG. 11 is a side view showing an alternative embodiment of a latch
mechanism.

[0035]FIGS. 1a and 1b show a traditional couch, that has become known as a
so called "health lounger". It comprises an integral seat assembly 1,
consisting of a backrest section 3, a center seat section 5 and a
footrest section 7. The seat assembly 1 is a rigid unit, typically
comprising an outer frame, in which a textile, slightly elastic and/or
cushioned support is held.

[0036]The entire seat assembly 1 may pivot about seat attachment axle 9
relative to base frame 11. Base frame 11 typically comprises a left and a
right base frame element 11' which are laterally spaced apart, and in
between which seat assembly 1 is located. Seat assembly 1 is connected to
and held by base frame 11 only through seat attachment axle 9.

[0037]Base frame 11 typically comprises four feet 13, two on each side of
seat assembly 1. Feet 13 are in contact with the floor 19, and are spaced
appropriately far apart to provide sufficient stability.

[0038]Through a weight shift seat assembly 1 can be rotated as illustrated
by arrow 15 in FIG. 1a from an upright position illustrated in FIG. 1a
clockwise into a reclined position illustrated in FIG. 1b. Seat assembly
1 thereby rotates about seat attachment axle 9. In the reclined position
footrest 7 assumes an approximately horizontal orientation. Through a
weight shift in the opposite direction, as illustrated by arrow 17 in
FIG. 1b, the chair can rotate back from the reclined position into the
upright position, i.e. until the front end of footrest 7 touches the
floor 19.

[0039]To facilitate the weight shift an armrest 6 is provided, which is
connected to or forms a part of base frame 11.

[0040]Getting onto and out off such "health loungers" is difficult,
because footrest 7 is always in a forward position in front of center
seat 5. An improved design is proposed, and discussed with reference to
FIG. 2 ff, whereby the same reference numbers have been used when
referring to comparable parts.

[0041]Referring now to FIG. 2, an exemplary embodiment of an improved
reclining lounge chair is illustrated. A seat assembly 1 is provided,
comprising a backrest 3, a center seat member 5, and a footrest 7. Center
seat member 5 and backrest 3 may form a subassembly, and assume a fixed,
predetermined orientation to each other. The subassembly of center seat 5
and backrest 3 may be a single, rigid part.

[0042]Seat assembly 1 is pivotally connected to base frame 11, i.e. both
the left and the right base frame members 11', by a horizontal seat
attachment axle 9. Seat attachment axle 9 may be a single shaft extending
from the left frame member 11' to the right frame member 11'. Seat
attachment axle 9 may also consist of two independent attachment members,
one each attached to left and right frame member 11'. Seat attachment
axle 9 may be any connection known in the art to pivotally attach center
seat member 5 to base frame 11.

[0043]Footrest 7 is connected to center seat member 5 by a horizontal
footrest attachment axle 23, which footrest 7 may pivot about. Footrest
attachment axle 23 may be a single shaft extending across the width of
the footrest. Footrest attachment axle 23 may also comprise two
independent attachment members, one on each side of footrest 7. Rotation
of footrest 7 about footrest attachment axle 23 is controlled by footrest
lift mechanism 25. Footrest lift mechanism 25 typically consists of a
pair of footrest lift bars 25', one on each side of the chair. The front
end of each footrest lift bar 25' is pivotally connected to footrest 7
with a front footrest lift axle 29. The rear end of each footrest lift
bar 25' is pivotally connected to the base frame 11 by a rear footrest
lift axle 27.

[0044]Referring now to FIGS. 5 and 6, a footrest lift function line 31 is
shown, which is a straight line extending from the front footrest lift
axle 29 to the rear footrest lift axle 27. Also shown is a seat member
function line 33, which is a straight line extending from footrest
attachment axle 23 to seat attachment axle 9. As illustrated, the
footrest lift axles 29 and 27 are positioned such that the footrest lift
function line 31 and the seat member function line 33 intersect.

[0046]Due to the disclosed geometry, an occupant's weight shift onto
backrest 3, as illustrated by arrow 15 in FIG. 2, causes the subassembly
of center seat member 5 and backrest 3 to rotate clockwise. The relative
position between center seat member 5 and backrest 3 remains unchanged,
since both are in a fixed relative alignment, and may form a single part.
An occupant may hold onto armrest 6 to facilitate the weight shift.
Armrest 6 may be connected to or form part base frame 11.

[0048]Rotation line 35, which indicates the relative position of footrest
attachment axle 23 to front footrest lift axle 29, rotates at least
60°, preferably at least 80°, and especially 90°,
when the lounge chair is adjusted from its upright position to its fully
reclined position. The illustrated rotation of line 35 causes footrest 7
to rotate correspondingly. In the chair's upright position, as shown in
FIG. 2, footrest 7 assumes an approximately vertical orientation towards
the floor 19. In the reclined position, as shown in FIG. 3, footrest 7
assumes an approximately horizontal orientation. In the illustrated
embodiment footrest 7 rotates about 90° between the chair's
upright position and the chair's fully reclined position. This provides a
comfortable reclined position, while also allowing an occupant to easily
enter and exit the chair in the upright position.

[0049]One aspect of achieving the desired kinematics is illustrated in
FIG. 3. As shown, rear footrest lift axle 27 is located below seat
attachment axle 9, i.e. below horizontal line 37, which intersects seat
attachment axle 9. Alternatively, or in addition thereto, footrest lift
axle 27 may be located in front of seat attachment axle 9, i.e. on the
left side of vertical line 27, which intersects seat attachment axle 9.
Front footrest lift axle 29 may also be located above horizontal line 37.

[0050]Footrest lift mechanism 25 has an effective length that is
determined by the distance between front footrest lift axle 29 and rear
footrest lift axle 27. Correspondingly, center seat member 5 has an
effective length that is determined by the distance between footrest
attachment axle 23 and seat attachment axle 9. The effective length of
footrest lift mechanism 25 may be 5%, and preferably more than 10%,
shorter than the effective length of the center seat member 5.

[0051]Finally, favorable kinematics can also be achieved, if the distance
between the seat attachment axle 9 and the rear footrest lift axle 29 is
short relative to the height of seat attachment axle 9 over floor 19. The
distance between seat attachment axle 9 and rear footrest lift axle 29 is
preferably less than 25%, specifically less than 15%, less than 10%, less
than 8% or even less than 6% of the height of seat attachment axle 9 over
floor 19. On the other hand, the distance between seat attachment axle 9
and rear footrest lift axle 29 should not be selected too short.
Favorably the distance between seat attachment axle 9 and rear footrest
lift axle 29 may be more than 2%, more than 4%, 6%, 8% or 10% of the
height of seat attachment axle 9 over floor 19. The same preferred
distance ranges apply to the distance between front footrest lift axle 29
and footrest attachment axle 23.

[0052]The disclosed embodiment is esthetically pleasing, as both footrest
lift bars 25' of footrest lift mechanism 25 may be "hidden" behind an
outer frame of center seat element 5. This can be achieved by disposing
footrest lift bars 25' immediately on the inside of the outer frame of
center seat member 5.

[0053]FIG. 7 schematically illustrates the reclining mechanism, by
superimposing a schematic view of the seat assembly 1 in the upright
position, an intermediate reclined position, and the fully reclined
position. The upright position is schematically also illustrated in FIG.
5, the fully reclined position schematically illustrated in FIG. 6.

[0054]Referring back to FIG. 2, a horizontal stop bar 65 is shown, which
extends between the left and the right base frame members 11' of base
frame 11. Horizontal stop bar 65 provides a stop for backrest 3, thus
limiting the movement of backrest 3, and defining the maximum reclined
position. Stop bar 65 is located at the base frame 11 such, that in the
thereby defined fully reclined position footrest 7 is oriented
approximately horizontal.

[0055]In an alternative embodiment, backrest 3 may pivot relative to
center seat member 5 by utilizing a separate mechanism, which is hinted
in FIGS. 2 and 3 by showing a backrest attachment axle 41. In this
embodiment a backrest locking mechanism must also be provided. It is
possible to provide a backward stop element, which limits the maximum
opening angle of backrest 3 against center seat member 5, but allows
backrest 3 to tilt forward against center seat member 5 to accommodate a
favorable storage position.

[0056]Referring to FIG. 4 it is shown, that the lounge chair may assume a
storage position, e.g. to minimize the space required to store the lounge
chair in extended periods without use, e.g. fall and winter. To achieve
this, backrest 3 may rotate around backrest attachment axle 41 forward
and towards center seat member 5. The chair can be folded further by
removing rear footrest lift axle 27 from base frame 11. For this purpose
rear footrest lift axle 27 may be attached to base frame 11 with screws,
which can be removed with the help of a tool, e.g. a wrench or
screwdriver, so that rear footrest lift axle 27 can be disconnected from
base frame 11. This allows further folding of the chair, until footrest 7
is parallel to seat member 5. Base frame 11 may be designed such, that
its front feet 13 can pivot around a front foot attachment axle 101,
which is located close to armrest 6 at each base frame member 11'. This
allows front feet 13 to swivel backward, further reducing the chair's
storage size. In its storage position the chair may be reduced to a
height of about 30 cm and a length of about 120 cm.

[0057]Even though the lounge chair can be operated as described, it may be
further improved by providing a latch mechanism 51. This is to prevent
the chair from accidentally reclining, e.g. by an unintentional weight
shift of a larger occupant. Latch mechanism 51 may be located between any
two parts of the chair that rotate relative to each other while
reclining. A suitable location for locating latch mechanism 51 is around
seat attachment axle 9, where center seat member 5 rotates relative to
base frame 11. Another suitable location is around rear footrest lift
axle 27, where footrest lift mechanism 25 rotates relative to base frame
11.

[0058]Latch mechanism 51 may be a friction mechanism, which increases the
amount of torque required to rotate two parts against each other, e.g.
footrest lift mechanism 25 against base frame 11. Latch mechanism 51 may
also be a step mechanism, providing incremental torque when exiting
predetermined recline positions.

[0059]An exemplary latch mechanism 51 is disclosed with reference to FIG.
8a through 12. The disclosed latch mechanism comprises a latch disk 53,
which may have the shape of a complete disk, or a partial disk. Latch
disk 53 may be mounted torsionally rigid to the inside of base frame 11,
e.g. around rear footrest lift axle 27. Footrest lift axle 27 will then
pass through a hole located in the center of latch disk 53. Latch disk 53
comprises radially aligned and circumferentially spaced recesses 59 and
protrusions 57. Protrusions 57 may be bars, noses, ribs, or any suitable
convex feature. Recesses 59 may be notches, slots, grooves, indentations
or any other suitable concave feature. Recesses 59 transition into
protrusions 57 in form of slanted slopes 61.

[0060]Footrest lift bar 25' of footrest lift mechanism 25 may comprise at
least one protrusion 65 that is suitable to engage recesses 59 of latch
disk 53. Alternatively, footrest lift bar 25' may comprise at least one
recess that is suitable to engage protrusions 57 of latch disk 53.
Footrest lift bar 25' may extend beyond footrest lift bar axle 27, and
comprise two protrusions 65, one on each side of footrest lift bar axle
27, and each engaging latch disk 53 at opposite ends.

[0061]Referring to FIG. 11, footrest lift bar 25' may move axially along
footrest lift axle 27. Footrest lift bar 25', which forms a sliding arm
relative to latch disk 53, may be pushed towards latch disk 53 by a force
acting in direction of arrow 68. This force may stem from pretensioned
latch spring 67. Latch spring 67 may be supported by rearward support
plate 69. Rearward support plate 69 may be held by a bushing 70 that
surrounds footrest lift bar axle 27 (not shown).

[0063]The amount of incremental torque provided by latch mechanism 51 when
rotating footrest lift bar 25' against base frame 11 depends on several
factors, among them the force of spring 67, the size and height of
protrusion 65, the height of protrusions 57 and recesses 59, and the
angle of slope 61. Referring to FIGS. 8a through 10a it is illustrated,
that all protrusions and recesses, as well as their height and their
slopes 61 may be dimensioned equal. However, the inherent torque required
to rotate footrest lift bar 25' against base frame 11 (i.e. without latch
mechanism 51) may vary for different chair positions. To equalize the
adjustment force required to recline the chair from each locked position
to the next if may therefore be desirable to create an inverted torque
profile for latch mechanism 51. Latch mechanism 51 can be designed such,
that the latch torque is small for reclining positions that naturally
require high adjustment forces, and vice versa latch torque is high for
reclining positions that naturally require low adjustment forces.

[0064]As illustrated in FIGS. 11 and 12, the slope angles α, β,
or χ relating to the slopes 61 may be selected differently, as may
width 57a of the protrusions 57, so that different "exit angles" cause
different incremental torque when entering or leaving various seating or
reclined positions. Exiting a particular latched position may require
different amount of torque, depending on which position is to be exited.

[0065]Finally, other latching or adjustment mechanisms are possible, e.g.
in the kind of a locking brake, e.g. to secure the chair in an
intermediate position, such that unintentional adjustment is no longer
possible.

[0066]While the present invention has been described with reference to
exemplary embodiments, it will be readily apparent to those skilled in
the art that the invention is not limited to the disclosed or illustrated
embodiments but, on the contrary, is intended to cover numerous other
modifications, substitutions, variations and broad equivalent
arrangements that are included within the spirit and scope of the
following claims.